SYMPOSIA PAPER Published: 01 January 1975
STP33166S

Microcrack Growth in Graphite Fiber-Epoxy Resin Systems During Compressive Fatigue

Source

Transfibrile crack extension in graphite fiber-epoxy resin composites was investigated in notched beams under cyclic compressive loading. Compressive fatigue crack growth was evaluated using selected linear elastic fracture mechanics parameters. A model was used to correlate observed micro-fracture processes with compressive crack extension behavior. Crack propagation underwent periods of deceleration and acceleration, and the crack growth rate dependence on material and environmental variables was determined. Transfibrile fatigue crack extension in unidirectional composites is a result of axial cracking and frequently resulted in crack arrest. Comparison of unidirectional composites with different epoxy resins showed the composite with the higher bond strength to be less susceptible to axial cracking along the fiber-matrix interface than the one with the lower bond strength. Crossplied (0°/90°) composites had lower compressive strengths, and through-specimen fractures resulted from axial cracking in the 0° plies, splitting in the 90° transverse plies, and splitting between plies. Exposure to a saline solution greatly increased axial cracking in all the composites and enhanced transverse ply splitting in the cross-plied material. Crack tip blunting and crack arrest due to solution-induced interfacial degradation was frequent.

Author Information

Kunz, SC
Cambridge University, Cambridge, England
Beaumont, PWR
Cambridge University, Cambridge, England
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E08
Pages: 71–91
DOI: 10.1520/STP33166S
ISBN-EB: 978-0-8031-4652-5
ISBN-13: 978-0-8031-0346-7